Since 2020, different countries worldwide are forced to opt lockdown as one of the measures to retard COVID 19 contamination. In the immediate effect of lockdown, the surface water quality of rivers and lakes improved as the industrial and human activities decreased. Also, the reduction of vehicle movement improved the ambient of water quality which is directly connected with the air quality. On contrary the presence of SARS-CoV-2 in the feces of infected patients has drawn attention to the prospective danger of faecal-oral transmission of COVID-19 by intake of river water. Also, the use of wastewater may be an epidemiological tool. This paper analyses the impact of COVID 19 on surface water quality parameters. Here the researchers selected the study area Ganga at Durgachak near Pathikhali, West Bengal, CPCB station code 1335. In this study, among physical parameters, Total Dissolved Solid (TDS), Total Suspended Solid (TSS), Total Hardness (TH), Conductivity have been studied. Chloride ion and Sulphate ion have been studied as Chemical parameters. Fecal Coliform and Total Coliform studied as biological parameters. Here researchers studied pre-monsoon and post-monsoon data before lockdown in 2019, during lockdown in 2020 and also in 2021 when restriction reduced. The water quality parameters also compared with last five years trend starting from 2017. Although the result cannot assure effect of lockdown completely, but most cases the water quality improved. It concludes that in normal situation also water quality can be improved if the policymakers, governing body take strict action to implement norms. It also suggests the urgent need for industrial and domestic sewage management which is directly discharged into the river.